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### Question: How to know you have hyperprolactinaemia?
### Response: Blood hormone test: In patients with hyperprolactinaemia, it may demonstrate elevated prolactin level, low testosterone level and low FSH and LH levels. Cranial MRI or CT scan: In these imaging tests, doctors may detect whether the pituitary tumor exists or not. Visual field examination: For patients with abnormal visual fields, visual field examination by an ophthalmologist is needed.